How you plant your new daylilies in your bed will be entirely up to you. You could group by height, color, tets or dips, evergreens or dormants, small blooms or large...there are almost limitless ways.
I don't group by anything most of the time, but some times the plants sort of pick their on spot. If your space is equal for each plant, you will find some outgrow that spot quickly while others never occupy the entire space. Some blooms will fade in the sun, some blooms won't open until late if they are in the shade etc.
So I say plant them any way you want the first year and observe them, then slowly as you get to know your plants you will start to rearrange them. Some will die some will try to take over, but it will be a constant pattern of change. I have never had the same arrangement among my daylilies for any prolonged length of time.
Some people have dedicated beds, maybe by names. There are so many possibilities.

This bed is in full sun and is 10' x 20'. I'm planting them 18" apart for now and see what happens. Luckily, if that is too tight (which it probably is) I will have numerous spots that will be opening up by this fall to move them. I have several varieties that I have several of and will be unloading those to make more room. Plus I've talked my husband into expanding another bed this summer. I also have alot of room where my roses are. For now, I'm just planting them according to height. I just wish this winter would get over so I can go play in the dirt!

I am not much of a landscape design person but these are the lessons that I learned from my mistakes:

- taller daylilies should be grouped together and put in the northern part of the bed so that they will not shade the shorter ones.
- if you wish to see a certain grouping of daylilies bloom at the same time, you should break them down by their blooming time. Maybe the bed can broken down to quadrants.
- know that eventhough you can try really hard to group them by height, some will grow taller and some will grow shorter depending on climate and soil. So like Larry said, they will let you know if they like a certain spot or look better in a different spot.

Susie you are getting great advice here I too like to see certain colors blooming next to each other and will place those colors next to each other providing the bloom time is similar. I also like to make sure I have early, mid, and late blooming in the same area so there is always something blooming at the same time throughout the beds. I try to make sure I plug in some early early and late late and definitely reblooming and bud builders to extent the blooming season.
The most important part is to have fun and enjoy your blooms!!!!!

It'll be "cozy" in that bed, but OK for a season or two. That will let you get a handle on how large and vigorous each plant tends to be, so you can site them with that in mind.

That's an important tip on orientation from @kousa. It doesn't seem as if it would matter much, but daylilies do most of their growing in the spring and autumn when the sun is lower in the sky, so shade from adjacent plants can make a big difference.

Similarly, I have found that a dormant daylily can have problems if it has evergreens as close neighbors. When growth resumes in the spring, the evergreens will shade it, out-compete it, and cause it to decline.

Similarly, I have found that a dormant daylily can have problems if it has evergreens as close neighbors. When growth resumes in the spring, the evergreens will shade it, out-compete it, and cause it to decline.

It would depend, though, on climate. Where I am all three foliage types start from scratch each spring because they're all killed right back to the ground in winter.

I am loving all the advice. I think I will take the taller ones and put them into a different bed with the lily bulbs I purchased. That why they would hide the dying foliage of the bulbs. One thing I failed to mention is that the sun comes up on one end of my house and sets on the other end. Later in the summer the sun will be further down in the sky so I might have to flip my entire lineup - final row first; first row in the final spot - the taller ones will be putting the shorter ones in the shade. The thing is you can walk around this entire bed. I'm so confused....